ENCE411 Exam 2

The flashcards below were created by user
may3rfan
on FreezingBlue Flashcards.

_____________ is an effective method for removal of volatile organic compounds (VOC's).

Stripping

What are some important examples of gas transfer in water ttmt?

1) oxygen transfer to biological processes

2) Stripping of VOC's

3) CO2 exchanges as it relates to pH control

4) Ammonia removal by stripping

5) Odor removal - volatile sulfur compounds

6) Chlorination, ozonation, for disinfection or odor control

What is occuring to the gas molecules when a jar of liquid is in equilibrium?

The number of molecules leaving the liquid is equal to the number of molecules entering the liquid.

What is the definition of solubility?

The concentration of gas in water at equilbrium

What is the definition of transfer rate?

The rate of which dissolution or release occurs.

Why is dissolved oxygen important for monitoring water treatment?

Too much DO can be lethal for aquatic life - "gas bubble disease"

Too little DO can prevent respiration, decomposition, and various chemical reactions.

The concentration of dissolved oxygen is higher/lower in the colder winter months of December through February, and higher/lower during the summer months of June through September.

Higher...Lower

The solubility of oxygen in water is much higher in lower temperatures. When the water is colder, there is less energy for the water and oxygen molecules to move, and the oxygen remains trapped in the water

kLa increases/decreases as airflow increases. Explain

Increases

The Kla value reflects the rate at which the water is uptaking O2.

What is added to the water to deoxygenate it? Why do we do this?

CoCl2 and Na2SO3

So that we can test the reuptake rate of oxygen in the form of DO

What is the procedure for finding kLa?

1) Deoxygenate water with stuff

2) Start Test (turn on aeration device)

3) monitor DO

4) Plot Cs-Ct over time on semi log graph

5) Slope = kLa

Adsorption

the process by which a substance (adsorbate) is collected onto the surface of an adsorbent to remove it from a water stream/the process by which “a surface” removes substances from water

Why is adsorption important in Water treatment?

Adsorption of contaminants in water onto activated carbon is often used for purification of water. Sorption processes are also important for the fate and transport of contaminants in the environment.